Escapement mechanism for typewriters and the like



Sept. 22, 1953 s. KHALIL 2,652,917

ESCAPEMENT MECHANISM FOR TYPEWRITERS AND THE LIKE Filed July 16, 1949 5 Sheets-Sheet l INVENTOR. Sax w AHALIL 44 TTORNE Y S. KHALIL Sept. 22, 1953 ESCAPEMENT MECHANISM FOR TYPEWRITERS AND THE LIKE Filed July 16, 1949 5 Sheets-Sheet 2 S. KHALIL Sept. 22, 1953 ESCAPEMENT MECHANISM FOR TYPEWRITERS AND THE LIKE Filed July 16, 1949 5 Sheets-Sheet 3 55750 KHALIL Q @Q 7 mm flTTORA/EY 5 Sheets-Sheet 4 S. KHALIL am? anal UNI-r Umr I ESCAPEMENT MECHANISM FOR TYPEWRITERS AND THE LIKE Sept. 22, 1953 Fiied July 16. 1-949 INVENTOR Sam-p KHALIL ATTORN EY Sept. 22, 1953 s. KHALIL 5 7 ESCAPEMENT MECHANISM FOR TYPEWRITERS AND THE LIKE Filed July 16, 1949 5 Sheets-Sh'et 5 INVENTOR. KEYED frmuz .4 TT oRNF Y Patented Sept. 22, 1953 UNITED STATES PATENT OFFICE ESCAPEMENT MECHANISM FOR TYPE- WRITERS AND THE LIKE 21 Claims. 1

This invention relates to improvements in rotary dog escapement mechanism for typewriters and the like, and is particularly directed to the provision of novel means which convert the reciprocating strokes of a universal bar into stepped rotary movement for rotating said rotary dog; and has for a primary object the provision of a converting mechanism which operates unerringly regardless of the speed at which a typist types.

The escapement mechanisms which operate with said rotary dog, are termed unidirectional, while the prevailing escapement mechanisms (widely used today) in which a dog or a dogrocker (carrying several dogs), moves back-andforth, for each typing action, are termed oscillatory escapement mechanisms.

Despite their superiority over the oscillatory escapement mechanisms for producing more uniform impressions, said unidirectional escapement mechanisms are discarded in favor of said oscillatory escapement mechanism.

The main reason for abandoning said unidirectional escapement mechanism in favor of said oscillatory escapement mechanism, lies in the speed limitation of said unidirectional escapement mechanisms. They do not respond to the modern high speed typing.

Said speed limitation of said unidirectional escapement mechanisms is due to the portions of the mechanism employed to change the reciprocal motion of the universal, bar into stepped rotary motion in one direction.

To change the reciprocal motion of the universal bar into rotary motion, said unidirectional escapement mechanisms employ a ratchet mechanism comprising a, ratchet wheel secured to the rotary dog, a propelling pawl which is motivated by the universal bar for driving said ratchet wheel, and a retaining pawl for said ratchet.

Other defects of said unidirectional escapement mechanisms such as, for example, weakness of their parts which are due to space limitation," will be described in the course of this specification.

My unidirectional escapement mechanism is, in many respects, and particularly in respect to its high speed of operation, superior to and novel as compared to all unidirectional escapement mechanisms of the prior art.

Having no drop movement, which is an inherent defect of said oscillatory dogs, and which is the cause of crowded impressions, my unidirectional escapement mechanism is also superior to said oscillatory escapement mechanism.

Unidirectional escapement mechanisms of the prior art As far as I know, among several unidirectional escapement mechanisms of the prior art, a U. S. patent, No. 514,807, was issued on February 13, 1894, to W. J. Barron and has, in certain respects, more resemblance to my unidirectional escapement mechanism than any of the others.

I will now briefly analyze the mechanism illustrated in said patent to conclusively show that it is impractical and will, by way of contrast, show the practical characteristics of my invention.

The mechanism which is shown in said patent may, for the sake of clarity of explanation and of comparison, be divided into two parts as follows:

(A) A double rack and a rotary dog, and

(B) A ratchet wheel and two pawls which I term herein, converting mechanism.

Rack and dog of Patent No. 514,807

Said patent shows a rack that has two parallel rows of teeth, the teeth in one row being arranged in a staggered order relative to the teeth in the other row.

It also shows a dog in the form of a disc having upon its periphery a series of teeth sulficiently spaced apart so that the space therebetween will permit the passage of teeth of said rack.

One of the defects of said rack, is the space limitation between the teeth thereof.

As an example of the defect of space limitation, suppose that said rack-and its associated dog, etc.-are to be applied to a typewriter for writing twelve (12) letters to the horizontal inch.

One inch (1") divided by twelve (12), is equal to a little over .083". Accordingly the distance between the center of one tooth of said rack and the center of the next tooth (of the other row) thereof will be .083".

Said .083 is to cover the thickness of one tooth of said rack, plus the thickness of one tooth of said dog, and plus the clearance between the tooth of said dog and the tooth of said rack;

To readily comprehend what is meant by clearance let us suppose that we are viewing said rack from the front, and it is adapted to move toward the left as the typing progresses. In this case the left side of a tooth of said rack, is (when the carriage is not moving), againstthe right side of a tooth of said rotary dog. Obviously, there should be a clearance between the left side of said tooth of said dog and the right side of the next tooth of the next row of teeth the thickness of one tooth of the dog, will be- Such thin teeth on said rack will not onl zjbe come weaker but are not mechanically jeasible if they were made of rollers or rods instead-ofa-flat surface.

(NrE.The teeth of my escapement wheel which is shown in Figs. 1, 2, etc., are cylindrical and can each be covered by an anti-friction roller.)

It is very advantageousctoquse such rollers, or t, least. o ltoi m. the t et oisa rac r of .said; dog, in order to reduce the friction betweenthe teeth of said rack and said dog sosas to as ly r t te said. o

Conce ina. mechanis -=01 at nt No.- 1.4.80?

Said patent.illustrates what-I term-herein a converting.mechanism It consists of a ratchet wheeliand'two pawlsandis-..intended to convert-" the.reciprocatingstroke of the universal bar into rotary motion-for rotating said dog.

Saidqratchet wheelis secured:to said rotary dogvandone of thestwo pawls is adapted to propelsaid ratchet=-whee1 whilenthe. other pawl is adapted to prevent said ratchet wheel from turning backward.

While-:moving back and: forth by=the typing action, said universal: bar-actuates said propellin rawlanc v sa re ult-0 vthis,. .sa d...rat et rotates one tooth.

Each: intermittent rotation of said -ratchet -by saidspawly rotates said dogone step andallows said rackto ad-vance one half the distancebetween two of the teeth in one row.

The maindefectof said converting mechanism is" speedlimitation ot-said pawl: and saidratchetwheels-- It is too slow for the modern-high speed typewriters.

Everything else being equal, the speed of opera tioneof =an escapementmechanism -is---the -predominant and--deciding factor.

Another important- -defect-of -said-.-'escapement mechanism-or rather-said doublerackpis in-themechanism employed therein-ion returning the carriage to the=left=hand marginal alignment; It 11 simply does not respond to -'the high speed-requirementsof modern-typing machines.

tical.

M y unidirectional escapement mechanism My unidirectional; ,escapernent mechanism is escapement j mechanism which-is -illustrated in said, Patent .No. 51 4,8 07, in ;manyrespects.

The ,mechanism of my unidirectional escapee? ment,- -the,subject of the-present invention, is, for

hesakeof clarity of, xplanationgand of com,-

parison, divided intotwo parts asiollows:

111A ub e apeme t w eel, and .a rotary;

(b) A novel-andhigh speedffconverting rneche,

ism-i difierent .from-and superior to-the unidirectional ,,5

My escapement wheel and dog In the preferred form of my invention I provide an escapement wheel which has two spaced parallel rows of teeth. The same number of teeth are employed in each row, and the spacing of the teeth in each row is uniform. The teeth in one of said rows are so positioned that if a line were drawn through any oneof its-teeth parallel to theaxis :of saidwheel it ;will bisect the interval between two teeth of the other row. This means that any tooth in one row is in axial alignment with the center of the space between two teeth of the-other row, as shown in Figures 1 and-'2.- This arrangement of teeth will be herematter called stag r Cooperating with this escapement wheel is a single: rotary dog, having teeth somewhat similar to the,,teeth of a gear, each tooth being adapted to engage the teeth of said rows alternately.

The width of each tooth of, the toothed dog is substantially equalto the axial-space between'a, plane extending through the centers of the teeth inone of'said rowsonthe escapement wheeland a plane extendin through" the centers" of*the teeth-in the other of said-rows as shown in'--Fi'g'- ure 5.

Normally, the center-of-one of the teeth of-said dog ism-contact withthe center ofone of the teeth'of one or the other of thetwo rows on'the escapement wheel, thereby-preventing the escapement wheel from rot-ating-under-the urge: of the mainspring This-is clearly showndn Figure 11.

During typing action theuniversal bar rotates saiddog-"one-half of the distancebetweemthe centers of two adjacent-teetn-ofsaid'dog; The' half-tooth interval of movement-of said'dog; by said universal bar,-displaces the tooth of the dog from contact-witha :given tooth in one row=-on'- the escapement wheelwith which it-was -in-contact'and-moves-it-into the path of the teeth-of the other row on the-escapement'wheel-p Accord ingly, the nextadjacent space between said-tooth (of-the dog) and the-nextone to itcomes into andremains across the-pathof said given tooth leaving it free'to' move therethrough. Since the escapement-wheel is rotatively urged-by the main spring of the carriage, it does rotate 'until' it is arrested-by -the engagement of the next-tooth, in said other row, with the intercepting tooth of the (10g;- Thuspthe escapement wheel, -in--a-singlemovement, efiects the-movement ofthe carriageone letter-space.

By the expression one-half of a tooth interval I .mean one-half of the width'of a tooth plus oneehalf of the .width ofthe space between-that tooth. and .-.the next adj acent' one. For example, the dog shown in Figuresi and- 2 has-12 teeth and.;12 spaces therebetween. Thereforeyitwill movein 24; steps for. each :complete revolutionthereof, each step eiTecting a letter spacing ofthe carriage One;0f:,the.advanta-gesand superior features of. my escapement; wheel; is this-.1 there. isv no space.- limitation between theteeththereofl; This.-en-; ables the choice of space intervals between the. teeth,.of,-my escapement wheel according to the Various factors involved;

For example, the teeth of,my escapementwheelv. may be made cylindrical asshown in :FigureswL; 2, etc., so as to reducezfricticnal.contact between .1. the, teeth of my escapementwheeland the teeth of .my*dog.. Being not restrictedto spacelimitaz tion,,the cylindrical teeth maybe made as :strong .i as required.

To further reduce saidfrictional contact,oanti.-;;- I

ment wheelof prevailing typewriters, for saidlast mentioned escapement wheel requires, due to its'lo ose and rigid dogs, a comparatively large interval between said teeth.

Converting mechanism of my escapement My converting mechanism, the mechanism which transforms the reciprocal movements of the universal bar into stepped rotation ofmy rotary dog, consists of:

(A) A ratchet wheel which is secured to my rotary dog and which has twice as many teeth as said doghas, so that therotation of one tooth of said ratchet wheel rotates said dog one-half of onev tooth.

(B) An oscillatory unit which is termed hereina propelling-unitand which is adapted to propel or rotate said ratchet wheel.

' Said propelling-unit includes two links termed herein toothed-link and shifting-link, respectively Said shifting-link is pivoted to the frame of my escapement mechanism while said toothed-link is pivotally mounted on the open end of said shifting-link.

. Each of said links is adapted. to be motivated in an ordered sequence in relation to the reciprocal strokes ofsaid universal bar.

Any motion which may be imparted to said toothed-link may or may not affect said shiftinglink, but any motion which may be imparted to said shifting-link, but'any motion which may be imparted to said shifting-link will impart a relative motion to said toothed-link. I

. (C) A driving-unit which is adapted to drive said propelling unit. It is pivoted on the frame of my escapement mechanism and adapted to be oscillated by the reciprocating-strokes of said universal bar.

Said driving-unit carries two selectors, one of which is adapted to motivate said toothed-link, and the otherone of which is adapted to motivate said shifting-link.

' Thus, both said propelling-unit and said driving-unit are pivotally mounted on the frame of my escapement mechanism. 1

' Said propelling-unit and said driving-unit together, are termed herein differential-pawl, as if they were a single unit;

'As shown in Figure 4, my differential-pawl, is on its return stroke, not in contact with my ratchet wheel, therefore both the teeth of said ratchet wheel and the tooth of said toothed-link may be'in the form of either ratchet teeth or any other suitable teeth. However, the teeth of said ratchet wheel are made ratchet-like. This enables the application to said ratchet wheel (not shown) of an additional pawl of the ordinary type, together with my differential-pawl;

Again as shown in Figure 4, the tooth of said toothed-link is made in the form of a stud so as to reduce the friction between 'it and the teeth of said ratchet wheel. friction an anti-friction roller -(not shown) may be mounted on said stud.

Operation 'Of my co'ncerting mechanism In its forward stroke, the universalbar swings said driving-unit in a clockwise direction as viewed. from the right side of a typewriter, and

To further'reduce said et wheel one tooth. The rotation of saidratchet wheel one tooth interval, rotates my dog one-half of a. tooth interval. Each half tooth rotation of my dog enables the carriage to advance a full letter-space.

, In its forward stroke said driving-unit engages said toothed-link and swings it in a counterclockwise direction, causing said ratchet to rotate one step in a clockwise direction.

After having propelled said ratchet wheel a given degree, said toothed-link disengages from said ratchet wheel, and from said driving-unit:

While said toothed-link is being disengaged from the tooth of said ratchet, the driving-unit, being still rotating in said clockwise direction, swingssaid shifting-link which in turn shifts said toothed-link so far awayfrom said ratchet wheel as to be enabled to swin back, under the tension of its spring, in a clockwise direction to a fixed stop without touching said ratchet wheel.

In its clockwise return direction, said toothedlink does not follow the reverse of the path that it had traced in its counter-clockwise direction. This is due to the shifted pivotal point of said toothed-link by said shifting-link.

As said universal barv returns to its normal position said driving-unit follows it and returns to its normal position.

The driving-unit, as it is returning toward its normal position, releases said shifting-link, which had been swung under the pressure applied thereto by one of the selector arms of said driving-unit; and as a result of this said shiftinglink, under the urge of a spring, returns to its normal position.

The shifting-link, as it is returning to its normal position, shifts back said toothed-link to its normal position along a path differing fromsaid clockwise path, from said shifting path which followed said clockwise path and from said counter-clockwise path.

Thus, in each oscillation of said driving-unit, the toothed end of said toothed-link traverses a somewhat quadrilateral path, comprised of said clockwise path, said downward shifting path, said counter-clockwise path, and said upward-shifting path.

In its upward shift the tooth of said toothedlink, enters into thespace betweentwo teeth of said ratchet wheel in alignment therewith.

Now, it can be seen that the path of said upward shifting of said toothed-link, is at an angle (for example, nearly a right angle) to said counter-clockwise path along which said toothedlink passes to rotate said ratchet wheel. That is,

said toothed-link reengages the space of the teeth of said ratchet wheel in a different direction than the direction in which it rotates said tooth. This enables my differential-pawl to engage and rotate said ratchet wheel as fast as any typist reciprocates said universal bar while typing.

Shifting mecms of my diflerentiaZ-pawl out downwardly, or toward which it is shifted steward ratchet-wheeli Anditheneai er thepointbf-"con=' tact of said di iving -unifi 'with said ishiffing me: is to the pivot'iot the latter: the fastewsai'd: tootheu link i isshifted .3 out fram saidiratchet wheel. t

The' anglePoishitting 'said toothed-link irt rea lation to the-t'e'eth of the-ratchet wheel; varies in: accordance :withithe variation: ofseveral fac to'rs such.as;:for 'example;.-the 'ositiomofithe pivot of: said shif-tirig-1inkion said-ermine, the"' length. 29

ofsaidhhiftingflinktthe length of isaiditoothed link; etc;

-'chan'ge='in said factors -nray and of-ten 'will'a change the-angle :betweemsaidzshiitine linka ands said' toothedqinm Any change oi th'e'angle 1312- 252i tween said shiftingflink and: saidi toothed link may; and :often'zw-ill; change th'e pathfsofi'shiftmg of said toothed-link tow'ards and from": said ratchet wheel Andzanyiichangepf theip'athr ofzf said toothed-link 'in reiationrto :theteeth of said 1' ratchet '-wheel maygaan'd .often -wilh; affect-the ease, the speed and the accuracyiof operation of i my convertin'gizmechanism;

Obviously," .the: easiest andIthe'mQstaccurate:

way o=:shifting-said: toothed linh in andout; is;

along Ta radial line, v that-is, -along a: straight line passingtth'rough:theircenters of said toothe'd -linka and said zratchet wheeL In the preferred form of my invention-theme sition :of the fpivotof said shiftingelink on the 40 1,

frame, thelengthof said shifting'elink the length': of .saidztoothedelink etci, are'so devised that at least atsone :position of contact between: said toothedelinkand said ratchet wheel; a 'radiailine 1-- is drawn from the center of saidvratchet -wheeifl 45,

across the center r of: :said lto'othed link land'- :it' is extended 'beyondr said toothed linkt it will pass through the center of :the pivo't' of: said:vtoothedlinkeon said :shiitingelinkn Fe'atiiresof my escapement "n'z'eci'zizriiskii" some" orthe important features 'ct my escapementniechanism' are as -fo11dws:

(A) All parts 'and 'elements of-"my escap'ement tial-pawl; are pivoted on their respectiveeem ters so to mini'mize their op'erative fr icti'onsii N6 pushin'g'hr pulling elem'entds' usedf To' for: ther-reducetheir operative friction ball bearingsp thrust 'bearingspetd (not shown); may-beapplied-mw to"saidpiv'ots (B3 The contact between' all cooperati've: e1'e-'- ments and 'part's 0f 'es(3911')(51111'131'117 mechanism: isadaptedto be made by studs' so as to'minimizef their operative frictional contact;

For example a stud or stub shaft isncar'ried on the open end of said toothed-link. It is extended-outwardly from both the i front and' th'e rear faces of said' t'ooth'ed-linkJ The extendedpart of said stud from the rear faceOf Said toQthed- 70 link is adapted to serve for a tootl i to-"en'gage and i'otatesaid-ratchet Wheel; while th'ebxtndd part of said stud from the fron't face -o f said toothed-link, is adapted to be engaged and driven b y thedrivin'gmnitf Anti friotibni rail; (not: shown may be mounted on each and a-H 'of sdld stiids to 'redfiee their frictional contact to aminim (C) Tfie di' iving uniti swan-ging am clcktvise' 1 direction on ite -forward i make;- oseillats -sai'd toothed lin 5 in cdunter 'clekwi'se direction? The selecting 'arm 0fsaid dniving unit contacts said eXte-ma}"stfid just slightly" below thewentr of the same, and cons'equ'ent-ly thetendencwof saidadrivingeunit is ":to rotate" said studinwsaid clockwise direction (which is the direction of rot'atidnofsaid" driyifig 'unltfi', thefebyenablifig the h'ol'dingf'of sai'd "stud"in"cooperatiiie''contact with the-tooth'of said-"ratchevwhefl "bymeans 'of' p a light spring.

(Di The disengaginghf-my'tocthed iink ifom itsratchet wheelf iseff'ected"'at"a position" where the 'pat-h 0f*r0tati011 of saidto othed' 'link, duetlj" its'counter=c1ockwisedirection,divergesfrornfthe path of rotation of said ratchet which rotate's inclockwisedirection? Duetofitsdiyerg'in'g path I said toothed link While approaching theposit'ion' where it is disengagedfrom' whetoothmf-"saicr ratchet, deceleratesthe rotatibn"thereof? (E YIn its"for-\trard"stroke mydiffrential' pawl" will rotate my ratchet wheel until said stu'dis" disengaged from 'said"ratchet'wheel*; thereupon ahy additfional' or"overtl'i'ro'w"stroke*of rny safd" difirential -pawl' cannot afieet the rotation ofsaid ratchet wheel, and accordingly anyot'er*-"- throw of-"said universar bariwill 'simply shift-"said toothed-dink farther away fro'm"'= sa1d-*- ratchet wheel, without, -hoWever,'-afictingthe rotation of saidratchet' wheel. I

(F) On its return str'ok'e; said toothed l-ink? bein'g 'out of eontact withmy ratchet wheel-, elihl inates frictional contact' betweenitselfand said" ratchet whee1 ,-hence I'caIl-" it a fre'e return 1ink'-= or pawl.

(G) Again;--on -its= return stroke-"said teothedlink; being-out of'-bontact-from said ratchet wheeljrequires oniy a lieht spring to =st'ving-.it madam clockwise direction-P (H) As it is being reengaged with the toothof my ratchet 'wheel', said toothed -lihkmove's, somewhatradially, intoengagement withisaid ratchet: wheel; whereby reboun'c'iingj vibration; et'c.' -will not affect said engagement in any manh'eri (1) No space -limitation between' the' teth -of eithermy 'eseapement wheel or 'my rotar-y dcga so that teeth of any sui-table outline and.dimen sion such 'as;7for example;:ro'dsxon 'other forms-of teeth-' whichi area-i shown:v in: the: accompanying; drawings may be useditorreduce theiufriction'al contact betweenn the: teeth of: my? escapement wheeliiand myz-rotaryi dogs:

(J) The=:possibility. of applying. anti-friction rollers (not'shownl fon said'.rods:':(teeth to Y fur ther-"rreduce or minimize frictionalwzcontact -be-' tween the teetnnof -my dog-eandemyi'escapement wheel.

(K=) -The" absence of any; particular require-- ment forsetting thew-universal bar-into oper tion by typingiactionpas my escapement -mech-* anism operatesmnder :anysand all sortsof typing strokes.

Referring", to the: drawings; which are given byiway of example? Figured is a diag-rammatic *representation' of: a typewriter, a portion .of-iwhibh:is brokemawayi to show my new and improved escapement mechanism in elevation as seen" along the lines" l-l os flig ure z;

mgure z is a v'iew of my escap'e'm'ent mech anis'm as' s'een along"the lines-2 2 01 Figure-'15 Figure 3 is a plan view of my escapement dog means, together with elements cooperating therewith, taken along the lines 33 of Figure 1;

Figure 4 is a series of step diagrams, each taken along the lines 44 of Figure 2, and showing the action of ratchet means on the escapement dog means and its relation to the universal bar on the typewriter;

Figure 5 is a fragmentary view showing the width of the teeth in my escapement dog means with respect to the center lines of the two rows of teeth on my escapement wheel;

Figure 5a is a fragmentary view showing the width of the spaces between the teeth in my escapement dog means with respect to the center lines of the two rows of teeth on my escapement wheel;

Figures 6 and 6a are charts showing the relation between the teeth on the dog of the form shown in Figures 1 to 5 inclusive, and the teeth in the double row on the escapement wheel and the movement efiected thereby;

Figure '7 is a front elevation of a modification =wherein the escapement wheel has a single row of teeth and the escapement dog has a double row of teeth;

Figure 8 is a side elevation taken along the lines 8--8 of Figure 7; and

Figure 9 is a plan view taken along the lines 9-9 of Figure 8.

Referring first to Figures 1 and 2, the typewriter includes a frame 20, keys 2|, type bars 22, a universal bar 23, and a carriage 24, upon which is mounted a platen and a rack 29. The carriage is urged toward the left, as seen in Figure 2, by means of a main spring 2! carried in a spring drum 23 and having a flexible extension 29 which is connected to the carriage 24.

A pinion 30 is keyed to the escapement wheel shaft 3|, and secured to the pinion 39 is a ratchet wheel 39. My escapement wheel 33 is comprised of two discs 34 and 35 connected together by a hub 36 which is freely journaled on the shaft 3 l. The shaft 3| is carried on supports 31 and 39.

'The ratchet wheel 39 is connected to the pinion 30 by means of a hub 49 and it normally abuts the face of the disc 35. Journaled on a stud 4| in the disc 35 is a pawl 42 which engages the teeth of the ratchet wheel 39 and constitutes the driving link between the pinion 39 and the escapement wheel 33. Cooperating with the ratchet wheel 39 is a push rod 43 which is actuated by the back space key on the typewriter. This push rod advances the ratchet wheel 39 one tooth when the back space key is depressed, thereby causing the pawl 42 to ride over into the next tooth. The ratchet also allows the carriage to be returned. For simplicity in describing the cooperation of the escapement wheel and the escapement dog to be presently described, the teeth of the escapement wheel are numbered so as to distinguish each tooth in each of the two rows. In other words, the teeth on the disc 34 are numbered 44a, 44b, 44c, 44d, 44c and 44 while the teeth on the disc are numbered 44A, 44B, 44C, 44D, 44E and 44F.

My dog device includes a wheel 45 which is provided with a plurality of teeth 49 with equal spaces 41 therebetween.

From Figure 5 it will be noted that the width of each tooth 46, and consequently of each space 41, is determined by the spacing of the discs 34 and 35 of the escapement wheel. It will be 'naled on the shaft 5!.

supported in a suitable hole formed in a boss 52 carried on the upper end of an upright support 53. The other end of the shaft 5| is supported in a similar boss 54 carried on an upright support 55. The upright supports 53 and 55 are joined by a horizontal portion 56 which may be secured to the frame 20 in any suitable manner, for example, by means of screws 51.

Driving unit The following elements comprise what I term my driving unit:

An arm 58 has a hub 59 which is also jour- The hub 59 has an enlarged portion 60 which abuts the ratchet wheel 49, and thereby the arm 58 is held in spaced relation to the ratchet wheel 49. Formed integral with the hub 59 is a sector 6|, the radius of which is longer than the radius of the ratchet wheel 49. Formed integral with the sector 6| is a second sector 62, the radius of which is substantially longer than the radius of the sector 6|. The arm 58 has a stud 63 extending to the left, as seen in Figures 2 and 3, and toward the rear, as shown in Figure 4, and journaled on this stud is a roller 64 which is adapted to be engaged by the end of the universal bar 23.

The arm 59 is normally positioned against a stop pin 89 and it is urged into engagement with the stop pin 89 by means of a spring 99, one end of which is secured to the arm 59 and the other end of which is secured to the upright support 55. The sector 6| has an active radial face Gla, and likewise the sector 62 has an active radial face 6211.

These elements comprise a driving unit which is actuated by the universal bar and which, in turn, actuates the shifting link of my propelling unit, to be presently described.

An upright member 65 has a base 66 which is secured to the horizontal portion the uprights 53 and 55 by means of Shifting link My shifting link is comprised of elements:

A lever 19 is journaled by the upright support 55, in Figure 4. This lever has a normally horizontal portion 69, and formed integral therewith on the right end thereof is a normally vertical portion H. The vertical portion carries a stud 12, which may best be seen in Figure 3, and carried on this stud is a ball bearing 13, which includes an inner race 14, a plurality of balls 15, and an outer race 76 which cooperates with the arcuate face of the sector 62.

The lever member 19 has one end of a spring 11 secured thereto, and the other end of this spring 11 is secured to the horizontal portion 55 of the support. Consequently, the lever member i0 is urged in a clockwise direction about the axis 98 into contact with an eccentric 18. This eccentric, as may be seen in Figure 2, has a hub 79, which abuts the upright portion 55 of the support and which is secured thereto by means of 56 between screws 61.

the following on a stud 68 carried as may best be seen married on the horizontal portion- 69 of the lever member is-a stud 8 I which has journaled thereon a roller'82.

-Toothed' link An arm '83, is rotatably. mounted .onfthe. .horizontal portion'BB of.thei1everl18by meansofa shouldered screw. 84. "This arm .has ,an extension '85, to which oneoen'd of..a"springT86, is secured. Theother. end of the spring, 86 .is. securdLtma "depending tab "81, which .is preferablyfformd i integral with the horizontal portion 69. .Thearm 83"carries. near its outer. extremity a' 'sha'it"88. A portin*88a cooperates with"the"teethf.58,6f the ratchet whee1"'49 and also with 'the sectof'Bl. The other portioni88b1ofl'the:shaft 88 cooperates "with-a. stop. shownhereinaatheupright. 65 which defines the at rest position of;.said'.link. ,The :arm 83 i. and .-its shaft .88 and. the;v portion 488D thereof. constitute my todthedllink. .Theilfunc- -tions f said toothed ,nnk .-will-.. be explained .in .'detail in connectionwith thas'ix-steps showmin "Figurexl.

.Propelling unit The elements :cf: my shiitingylink, described abovegandtfthei elementss-niimy ltOOthed E1ink;:car-

IiGGFOHLthQR shifting dink,- constitute: what I' term -:herein I my -propellingzunit ,becauseftheyztake: the reciprocating-motion zottheirun'iversal bar via my @driving ;unit;iand delivereitztofthe:ratchewwheel 7A9, causing:the-.1atter .tozrotate in steps.

0peratz'onof" th'e'ratchet 'wheiel49 --Whena .keyzsuch asitheikeyrzlisis depressed, a :typeibausuch as the type ibari 2'2 isrmoveditoward @the platen in theeusual'mamier. :l-During' that .-.time,-lthe universalbar; 23-moves towardfiheright, as seen inFigures 1-:;and.:4. rfleferringz-morezparticularly to Figure.-.4 A,a L-show the ratchet-wheel 49 .andits cooperative C elements: in T'thBiI; mormal positions. The arm 58 of the drivingiunit isiheld in vcontact with-the stop;pin.-8Babyzmeansrofithe spring-:90 and .the arm-.83. iotatheetoothedrlinkris at rest with its shaft portion. 88 b: inmontact with the upright 85, and-.with 88a.:irrcontact; withithe .radial face- .61 a l of the sector-"6 I of' z-thezdriving ..unit. .The lever-member;fllhofcthe-shiftingadink is in. contact ewith-vthe eccentric? a18,uduecto fiche urge of the spring TI, andthe ball bearing 13 is in contact with the'arcuate 'face of the sector -62 of the drivingiunit.

Now, breaking down the advance of theiuniver- .sal bar: :In ,FigureAB-ithe. =universal" barf 13.,1has radvancedvslightly. The endiofzthisbar: has engaged the roller Bland. .has xa'dvancedzthe" arm ,58 of r the driving unitsligh-tly': inaa'rclockwise :direction. The radial face 161 a of the .SGBtOI'I :onthe driving unit hasengaged the 'shaft''88,

which is the tooth of mytoothedflink;.andrmoved it into engagement with the ratchet wheel tooth 50a. It will also .be noted that theasector; B2 on the driving unit has moved:downwardly acorresponding amount, and theball. bearing'13 t'onithe .shifting linkis in contact with the'curved'sur .lface .-of said sector-.62 at. a point-:nearerato the imid portion thereof.

In. Figure 4C;the..-'arm:--58 has been-pushed by the universal :barv 23 to :a;;p0sition =where it' is .alrnost vertical. In thisg-positionathe. radial edge .Gla ofthe sector. 6 I: on the driving .unit. has moved the shaft 88 on thetoothed-1ink1and1the*arm 83 supporting it -.inacounter-clockwise:direction to 12 ea point where" thevshaft-l88 .isajustaboutzto'deave athe ratchet too'th 350a, nthereby iztensioningtsthe spring 862 By this movement, therratfchett-todth 58a has advanceduin a clockwise direction'ra'idis- =15 'tanceequal to-oneitooth. :The -sectorr82- nnzlthe "driving unit has *moved :downwardlyotozarpoint :wherethe'ba'll bearing 13 ontthezshifting unit;is in contact with the upper;portionwofztheecurved 'surface' BZ of the driving-.unittand is almostnready 7 1o to pass off of thessame.

-In Figure 4D,:rthe. azrrmBB zhas1beerrzpushed rby the universaltzbar 23:,.to;-:a:positioncbeyond' the vertical 1plane,".the: shaft'zfl 8 ,'.:which ::is the:- tooth ,of the .toothedzlink;dsun contact withtthe arcuate '15 surface zofizthasectorlfi I" of: thezdri'vinganniteand the :arcuate surface: of; the zsectori 62 :Df; themame unit has been moved out of contact with thahall "bearing 13::onr1thenshifting linkgandrzitsrzradial trace 18211 is inncontact' with:the.: roller;82::omthe 9c islever .membenflo :ofctheishiftingulink. LSinCB'JIhE shafta88 =(ortooth);mas beemcanunedzdownwardly by the sector fiL-gitmas' lefttrthe faoothvfifla: ing-a upositionawhereothenzooth has:.been: advanced a zspacexequal toiithezdistancei'from: one ctonthtto 25 thezothersof the ratchetmwheel'ifl, ;and .thedever member '20 of the shifting link ististill 'heldinn contactawithithe eccentric stop'lflxby meansxiiithe spring 11.

t-Referring' .to :Eigure' 4E, itherarmi 58 :hasnbeen ":m still further advanced by the nnivers'alihanfl,

- and theradittltfaceflazof Lthe sectorzonrhhezdrivking unit, actingiagainst .thewollenBZirhas'swnng othe lever: memberflocof .thezshifitingnlink about ..the;axis 68 inia counteraclockwisadirection. iiDue ratothe'zfacttthat:thesradius: betweenvtheiaxis 8 l;-o'f the 11011611182.BJIdZthGPELXiSaS8FSUPDOItiDgdZhGZ18YEI' imember imis 'short, ."jthis;moviement.mas been substantial anwizherarmiwiofjthet toothedrlink, it is assumed, has not yet been moved im a'clackwisedirectiorrzunderithe urgeioflthe spring: 85.

Referring znowrto: Figure 5 4F,':.which :showsethe arravan instant.;later,:-' .the2spring) has moved :.the armiz83zrinx a: clockwise. directionauntik'iti has been";arrestedcbyathe'reontactnofizthejshaftz 881M v .the'-.1toothed'rulinkwwith thB'TVEI'fiCfllISUIJDDIt:35. -.-When .ithe :universali:barrreturnsiztherrannr 58;.6f :-.the;driving;unitzunderiatherurge of thes'spring 8.0, ireturnszito;.itsmormaL-positionain contact with :therstopiBB. p-The sectors Bl and'ifizi also return :toztheirrznormal; positions,':.which:are ,thezaposi- .;ti0ns:show1r. irr.E igure AA.

...'Now..since.;the;radial f ace, 6Zmzofithersectohfikis byzthis movement; disengagedl'fromizthe; rollerdfl gther-lever member 1:10 of zdahexsslriiting;;1ink-:.zis 5 asnapped' back-. to. itsxnormal'uposition, :innconta'ct ,Withthe-eccentric fl 8 ,nn'deri the;urge;of the'spring 11. :l-Iowever, -the:sectorzfi2.rof the;driving:iunit, moving to ;itsunormaluposition,: prevents ifthe lever member 10 of the-rshittingalink irom'rre- 60 .zbounding, due to the-=em;agementof -::the1"ball zbearing .13- with the arcuate surface .ofithesector. ":.The shaft 88' of' the' toothed link, which :was urged; into .contact' with the: VE'EtiCEIvSUDDOItF-fii ibyipmeans ofzthe spring 86 describedrabovm'may :reboundras it. strikes thesupportdi5g:but;zas:noted from FigureA-F; anarc 86a; drawn iromzthecpoint of -.the -.tooth;: fiflb'iaboutsz therax-iszi 6.8:..showsi that, even with substantial reboundingbf thei -shaft 88 ,1. thisrshaftxor; tooth:isxcertainutospass;into;:the tspace=between theiteethififibgandi58caas ztheilever 18 returns to its normal rposition.

Operationofthe escapement -Due':to the factdzhat::the ratchetiwheel 49 and rtheizescapement:dogsywheelw-fi are connected: to-

13 gether by the hub 48 to form a unitary structure, the movement of said ratchet wheel 49 one tooth, causes the escapement dog wheel 45 to advance one-half tooth.

Referring to Chart A in Figure 6, the dog 45 is at rest and the escapement wheel 34, 35 is at rest.

This is the position shown in Figure 1. Charts B, C and D in Figure 6 show the breakdown of the movements of the elements while efi'ecting one complete letter space. As a key is being depressed, the escapement dog wheel tooth 46a is moved from the position shown in Chart A of Figure 6, where the escapement wheel tooth 44a in the row 34 is arrested. Now this dOg tooth must arrest the next escapement wheel tooth in the second row to effect a letter spacing, and during the first portion of the movement of the dog tooth 46a it has moved to a position where its extremities coincide with the center lines of the two rows of escapement wheel teeth, the position shown at Chart B in Figure 6, which is also the position shown in Figure 5. In this position the escapement wheel is still locked against movement because the dog tooth 46a has not yet moved out of the path of the escapement wheel tooth (1. In Chart C of Figure 6 the escapement dog tooth 46a has completed its movement and is in alignment with the tooth 44A in the row 35 of the escapement wheel, and at the same time the space 411) between the dog teeth 46a and 46b is in alignment with the teeth of the escapement wheel in the row 34, so that the tooth 44a is free to pass through this space, and when it does so the escapement wheel is arrested as soon as the escapement wheel tooth 44A contacts the dog tooth 46a. This is the position shown in Chart D of Figure 6. The dog tooth 46a remains still and the escapement Wheel is arrested thereby by the engagement of the tooth 44A with it. Thus one complete letter space is effected.

It will be noted that during the first part of this movement the escapement dog rotates, and during the latter part of this movement the escapement wheel moves and the escapement dog comes to rest and arrests the escapement wheel. Charts E, F and G of Figure 6 show a breakdown of the movements of the elements for eflecting a second complete letter-space. In Chart lit the escapement dog has rotated to a position where the extremities of the space 41b between the teeth 46a and 4612 are in alignment with the center line of the two rows of teeth on the escapement wheel. It will be noted, however, that the tooth 46a is still in engagement with the escapement wheel tooth 44A. Now as the escapement dog rotates further, the space 411), as shown in Chart F, is brought into alignment with the escapement wheel tooth 44A and the latter is free to move therethrough. At the same time, the dog tooth 46b is moved into alignment with the row of escapement wheel teeth 34 so as to arrest the escapement wheel tooth 4413. In Chart F it is assumed, for purposes of illustration, that the escapement wheel has not yet started to move. However, it does move because the tooth 44A on the escapement is free to move through the space 41b and the tooth 44b in the row 34 of the escapement wheel comes against and is arrested by the dog tooth 46b, as shown in Chart G, and thus a second complete letter-space is effected.

As a matter of fact, the dog wheel starts moving while the escapement wheel is locked against movement. The dog wheel releases the escapement wheel and comes to rest, and the escape- 14 ment wheel moves until one of its teeth in one or the other of said rows is arrested by the one of the dog wheel teeth which is in its path.

The chart Figure 6a shows the relation between the teeth of the dog and the teeth of the escapement wheel at rest. The first position A represents the initial position of the carriage. The Chart D shows the relation of the teeth of the escapement dog and the escapement wheel when one unit of letter space has been effected, and the Chart G shows the relation of the escapement dog and escapement teeth when a second unit spacing of the carriage has been effected.

M odificatz'on Figures 7, =8 and 9 show a modification of the form of the device shown in Figures 1 and 2. The ratchet wheel and the cooperative driving unit and the propelling unit for changing the reciprocating movement of the universal bar into intermittent motion in one direction, may be the same as that described above and I show those elements as designated by the same numerals and/or symbols as were applied thereto in connection with the description of Figures 4A, B, C, D, E and F, consequently the description need not be repeated.

In this embodiment of the invention, I provide the escapement wheel with a single row of teeth and the dog wheel with two rows of teeth. The escapement wheel I94 is journaled on the shaft 3| and carries the pawl 42 which engages the ratchet wheel 39 in the same manner as in the arrangement shown in Figures 1 and 2. The escapement wheel carries teeth 92, each of which comprises a shank 93 with a ball 94 on the outer extremity thereof, arranged in a single row. For convenience these teeth are designated as 92, 92a, 92b, 920, etc.

Cooperating with the escapement wheel I04 is an escapement dog wheel 95 which is comprised of a disc 96, and a second disc 91 spaced apart therefrom by a hub 98 preferably formed integral with the discs to form a unitary dog wheel. This dog wheel may be integral with or positively fixed to a second hub 99 which carries the ratchet Wheel 49. This array is journaled on the shaft '5I, and as the ratchet wheel is advanced, as described in connection with Figures 4A to 4F, the escapement dog wheel 95 is advanced.

The disc 96 has teeth I99 formed thereon with spaces I9I therebetween, the teeth and the spaces all being of the same width. The disc 91 has teeth I92 formed thereon with spaces I03 therebetween. The teeth on each disc are in axial alignment with the spaces on the other.

Operation Referring to Figure 9, the escapement wheel tooth 92 is normally arrested by the dog tooth I99 on the disc 96. Now when a key is depressed and the universal bar advances the ratchet 49 and, consequently, the dog wheel 95 one step, the dog tooth I is moved in the direction of the arrow, Figure 9, to the position which the space IOI7c had just previously occupied. Coinaesz; 9.1 7

315 athenescapement .tooth 92ra/I1daiimiS treeetozsmove the direction 10f :t-hearrow. Byutheatime the dog tooth :lillfl has :elearedwthe escapementn-tooth, 1 :the-dogtooth i Hi-has .overlappedthe; path of the escapement-toothehasoithezttoothe 92. isvarrested ,;by.-the .d og' tooth zifliasf'it ist-releasedlbyt-theidog tooth. I06, and .the movement of the escapement wheel .resulting fnomo thel-movement-s' oi-itstooth :92 from the point/where .it is-iseleased byitheldog Itooth- 100, to the point-wherecit is arrested by the .dog. tooth-v I ilk-effects one full, complete letterz space in a; single'movement of the carriage contnolled by .thesesca-pement mechanism.

During the next movement of the universal bar to effect a second'letter-space, the dog tooth I02 ;:.moves' to-ithe right one step :and releases the "escapement tooth 92. -At"the :same time, the zjjdog tooth Ulla. moves .intot-he path offa-ndarrests the escapement wheel tooth 92a.

From the above description-itwill be seen that,

,in thefirst form described, theescapement wheel :has: teeth arrangedin staggered fashion in' two .1WS 3 nd the dog wheelhas itsrteethvarranged ,inaa .single row,-wh-ile .inv the modification the {escapement wheel has itsfl'teeth :arrangedmin: a. ;;;single. row and thedogwheel hasits teeth arwheels carrying a single -.row,:of.:teeth.-on its peripherywhile the other one carries'two parallel rows of 1 teethv on its: periphery,:thecteethinione of said last-:rows being disposedz-int a; -staggered order' relative to those. in' the adjacentn'ow; said wheels being" mounted on shafts; at! right .angles to each other so-thatz'said: dogawheel forms :an :intermittently rotatable limiting stop againstthe rotation of said .-.escapement wheel,.;:a :ratchet .:wheel movablelwith .said'idOg whee1,-:a driving .unit -actuated by -.said universal :bar; and :1 a" pro- *pellingounitsactuatedi by said driving .aunit and including iaitoothed link cooperating :with-said ratchet wheel.

2. In a typewriter, a frameykeyson said frame,

a carriage movableonsaidiframe, a universal bar moved by the action of said keys, an escapement mechanism operatively connected to said 'carriage and including a rotatable escapement wheel and-arotatable dog wheel meshing with each other and having supporting shafts in said frame with their axes 90 apart, one of said wheels having a single row of teeth on its periphery while the other one of said wheels has two parallel rows of teeth on its periphery, the teeth in one row'thereon being staggered with respect to and "substantially spaced apart from those in the adjacent row, a ratchet wheel keyed to the shaft of said dogwheel, a propelling unit on said frame and including a toothed link cooperating with said ratchet wheel, and a driving unit for said propelling unit pivoted on said frame in cooperative relation with said universal-bar.

3." In a typewriter, a frame, keys on said frame,

a carriage movable on said frame, a universal bar :on-xsaid fra-memoved by thevactioni-ofi,saidckeys, tan :escapement" mechanism includingra rotatahle escapement-wheel and'a-rotatable dog-wheeh-one of said wheels having a single rowziofi wteethxon its periphery: and-.the other having two iiparallel rows-of teeth on its per.iphery,,.-.the;teethrinr one iofs-said last rowsibeingestaggered with-respect to the teeth in the other, the intervaLAeetween the centers of the-teeth of said:escapementwheel :1 substantial thickness: and: outlineowith :s-ufiicient aspace between said teethxfor -the:=teeth-.oesaid -.=dog wheel to also have: substantial ithick-ness *and outline:individual-shafts rjourna'led .inisaid irameand supportingsaid-. wheels',i means opera- 1 tively connecting saidescapementiwheelato said carriage; av ratchet-wheel keyed itotthe-shaft-tor isaidw doglwheel; a i propelling, uniton said..:fra-me being sufiiciently large oral-said teethitoahave 'zlincluding -L a toothed linktoooperating with; said -a;-reference point :fomsaid: link, and addr-iving unit .on said; frame:.operativelyaconnected to .said propelling unit zandi actuated -.bys said; 1 universal tbar.

vv wheel and av rotatable :dog -wheelgronerofi said vmovementof said universal bar.

ratchet wheel; stop means' on said -frameiforming 7 4.. ma typewriten. a frame; keys'lon said frame,

a carriage :movab'le' on:=said-frame;.a universal :bar moved: by tbGvEtCtiOH-Of. anyaofssaidikeysaan escapement-tmechanism:operatively- :connectedtto said 7 I carriage and including, :a. -rotatable,ruescape those in the; other, :ther spa'ce betweemthe -teeth 2 of said :escapement wwheelra-accommodating the :thicknessof the teeth: of=-said::dog wheeliplusoa aminimum :olearancefor-"reducing shock,i;i noise,

and wear-such. as are: present. in: otherzty-pes fof typewriters .rwhere the-clearance; is,1 of: necessity,

cured v on the-shaft, ,of 'said vdog wwheel;rand";high

r-speed pawlvmeans' and controls therefore-between saidiuniversal .bar and said .ratchet wheeleftective to advance said wheel-e during the forward .15.-'Ina typewriter, a frame,zkeys 'ontsaid-irame,

.ia carriage movable on said. frame, i a: universal .bar ,rnoved :by anyof -said keys-:an-escapemerit ,menchanism operatively connected i'to-.rsaid';zcarriage and including a rotatable-escapement-wheel and a rotatable dog wheel individual shafts journaled: in: said frame. and supporting saidwwheels, one .101 said. wheels carryingt on its periphery-a single row of teeth andi. the other .ofrsaidt wheels ..carry1ng on" its i periphery .two: spaced parallel .rows .of teeth, the teeth in one rowrbeingstaggered relative-to those in the oth'er,--the width of .eachitoothon one or" said wheel at.--,the.=periph- .said ratchet Wheel and said universale-bar effective .to -.advance said ratchet wheel duringa predetermined portion of the forwardtmovement of said universal bar.

6. In atypewriter, a frame,- keys on' sai'd'f-rame, a carriage movable on.--said..frame, .-a-funiversal bar movable forward and back as a resultzof: key action, an escapement =mechanism operatively connected: tov said carriage and including at rotatable escapement .wheel and avrotatablemdog wheel," one of said'wheels carrying a single row of' teeth on its'periphery,'and the other of said wheels carrying two spaced parallel rows of teeth on its periphery, the teeth in one of said last rows being staggered with respect to the teeth in the other, the width of each tooth on one of said wheels being substantially equal to the distance between the centers of two adjacent teeth on the other wheel, individual shafts journaled in said frame and supporting said wheels, a ratchet wheel carried on the shaft of said dog wheel, and high speed pawl means actuated by said universal bar during a predetermined portion of the forward movement thereof, said pawl means includinga toothed link normally engaged with said ratchet Wheel and disengaged therefrom during said predetermined portion of said forward movement.

7. In a typewriter, a frame, keys on said frame, a carriage movable on said frame, a universal bar movable forward and back as a result of key action, an escapement mechanism operatively connected to said carriage and including a rotatable escapement Wheel and a rotatable dog wheel, a single row of teeth carried on the periphery of one of said wheels, and two spaced parallel rows of teeth carried on the periphery of the other of said wheels, the teeth in one row on said last wheel being staggered relative to the teeth in the other row, and the width of the teeth on one of said wheels being substantially wider than the teeth on the other, individual shafts journaled in said frame and supporting said wheels, a ratchet wheel carried on the shaft of said dog wheel, and high speed pawl means actuated by said universal bar during a predetermined portion of the forward movement thereof, said pawl means including a toothed link normally engaged with said ratchet wheel and disengaged therefrom during said predetermined portion of said forward movement.

8. In a typewriter, a frame, keys on said frame, a carriage movable on said frame, a universal bar movable forward and back as a result of key action, a unidirectional escapement mechanism operatively connected to said carriage and comprising a rotary dog wheel having peripheral teeth thereon, a ratchet wheel operatively connected to said dog wheel and having twice as many teeth as said dog wheel has, a driving unit moved by said universal bar, said driving unit having a first and a second cam means, a shifting unit pivoted on said frame and actuated by said first cam means, and a toothed-link pivoted on said shifting unit in cooperative relation with said ratchet wheel and adapted to be actuated directly by said second cam means and indirectly by said first cam means acting against said shifting unit, each oscillation of said driving-unit being adapted, through said driving unit and said shifting unit, to cause said toothed-link to effect the following steps sequentially; the rotation of said ratchet wheel a given degree, the disengagement from said ratchet wheel, the swinging backwardly, and the reengagement with the next adjacent tooth on said ratchet wheel.

9. In a typewriter, a frame, keys on said frame, a carriage movable on said frame, a universal bar movable forward and back as a result of key action, a unidirectional escapement mechanism operatively connected to said carriage and comprising a rotary dog having a plurality of teeth disposed about the periphery thereof, a ratchet wheel secured to the axis of said dog and having twice as many teeth as said dog has, a toothed-link adapted to oscillate about a plurality of pivots and normally in operative en- Easement with said ratchet-wheel, a shifting unit pivoted on said frame and having said link pivoted thereon, thereby providing said plurality of pivots, a driving-unit having a first cam thereon and a second cam thereon, said first cam being arranged to actuate said toothed-link directly and said second cam being arranged to actuate said shifting unit, and a universal bar to actuate said driving-unit, each oscillation of said driving-unit being adapted, through the medium of said cams, to swing said toothed-link about said pivots sequentially for causing the same to rotate said ratchet wheel a given degree, to decelerate the rotation of said ratchet Wheel at least at the end of its movement through said given degree, to shift outwardly in spaced relation to said ratchet wheel, to swing backwardly, and to reengage the next adjacent tooth of said ratchet wheel.

10. A typewriter according to claim 9 in which said first cam has one surface extending in a general radial direction, another surface which is arcuate, and another surface, which might be termed a corner surface, joining said first and second mentioned surfaces, said first surface b ing adapted to engage said link and advance it in a direction to advance the ratchet wheel, said corner surface being adapted to cause said link to decelerate said wheel, and said second mentioned surface being adapted to hold said link out of engagement with said ratchet wheel.

11. In a typewriter, a frame, keys on said frame, a carriage movable on said frame, a reciprocating universal bar controlled by said keys, a unidirectional escapement mechanism operatively connected to said carriage and comprising a rotary dog having a plurality of teeth on the periphery thereof, a ratchet wheel secured to the axis of said dog and having twice as many teeth as said dog has, a propelling-unit pivoted on said frame and including a pivoted link carrying a stud which normally engages a space between two teeth on said ratchet wheel, and a driving-unit having a first cam to actuate said propelling-unit, and a second cam to actuate said link, said universal bar being adapted to oscillate said driving-unit, each full oscillation of said driving-unit causing said stud to make a round trip along a somewhat quadrilateral path, thereby advancing said ratchet wheel one step and engaging the next adjacent space on said ratchet wheel.

12. In a typewriter, a frame, keys on said frame, a carriage movable on said frame, a universal bar oscillated by the action of said key an escapement mechanism operatively connected to said carriage and including a toothed escapement wheel and a toothed rotary dog, both of which are mounted in said frame with their axes apart, a ratchet wheel movable with said dog and having twice as many teeth as said dog has, and differential-pawl means comprising a propelling unit and a driving unit, both of which are pivotally mounted on said frame, said propelling unit having a toothed link pivoted thereon in operative contact with said ratchet wheel, said driving unit cooperating with said universal bar and having a first control thereon to actuate said toothed link and a second control thereon to actuate said propelling unit, said driving unit adapted to be oscillated by said universal bar and adapted in turn to oscillate said propelling unit along a path extending in a plurality of directions, thereby rotating said ratchet Wheel through a given angle in a single direction.

13. In a device for transforming high quency reciprocal strokes into stepped rotary movement, a frame, a ratchet wheel rotatably mounted on said frame,a propelling unit pivoted on. said frame and including a pivoted toothedlink oscillatable about both pivots and normally engaging a space between two teeth of said ratchet wheel, a driving-unit journaled on said frame and carrying at least two selectors each of which is adapted to drive said toothed-link about a different one of said pivots, and reciprocating means to oscillate said driving-unit, each oscillation of said driving-unit causing said selectors to sequentially oscillate said toothed-link about said pivots, thereby causing said toothed-link to rotate said'ratchet wheel one step while advancing along a first path, to shift away from said ratchet wheel while moving along a second path, to decelerate the rotation of said ratchet wheel at least while disengaging therefrom, to return along a third path different from said first and second paths, and to reengage with the next predetermined space between teeth on said ratchet while moving along a fourth path differing from said first three paths, said link being entirely freeof and spaced apart from said ratchet wheel between the time it is disengaged from and the time it is reengaged' with said ratchet wheel.

14. The invention according to claim 13, in which said toothed-link is so arranged that the second and the fourth paths only are increased and decreased as the length of stroke of said reciprocating means is increased and decreased respectively.

15. In a device for transforming high frequency reciprocal strokes into stepped rotary movements, a frame, a ratchet wheel rotatably mounted on said frame, link means arranged to be oscillated about a plurality of spaced pivots and carrying a stud which normally engages a space between two teeth on said ratchet wheel, a member supported on one of said pivots and carrying said link means and the pivot supporting it, and an oscillatory driving-unit carrying a first cam to actuatesaid link means and a second cam to actuate said member and to thereby controllably drive said stud about said pivots, each oscillation of said driving-unit causing said stud to move in a sequence, wherein said stud first moves along a forward path, then veers along a second path, then moves backward along a third path, and finally veers along a fourth path towards its normal position and enters into the next and predetermined space between teeth of' said ratchet wheel, thereby completing a somewhat quadrilateral path which results in the rotation of said ratchet wheel by said stud.

16. In a device for transforming high frequency reciprocal strokes into stepped rotary motion, a ratchet wheel, a free return pawl positioned to be motivated by said reciprocal strokes and adapted to engage and rotate said ratchet wheel, multiple supports for, said pawl and dual cam means acting sequentially againstjsaid multiple supports for said pawl for causing the latter to sequentially reengage with successive teeth of said ratchet wheel in timed relation with the occurrences of said strokes regardless of the frequency of the same.

17. A free return pawl oscillatable about two spaced pivots, one of which is devised to enable said pawl to oscillate in one direction, and the other of which is devised to enable said pawl to move in a second direction, and driving means for effecting the oscillation and including cam means of one radius for controlling the movement of said pawl in said first direction anda' cam of a different radius for controlling the.

means having cam means'acting against one of said members and a second cam means acting against the other of said members, the axis of said cam means coinciding with the axis of'said' ratchet Wheel, and the axes of all said pivots lying outside the periphery of said ratchet wheel.

19. A toothed wheel, a toothed linkto rotate said wheel unidirectionally in steps, and compound cam carrying means having an axis coinciding with the axis of said toothed wheel cooperating with said link to decelerate the rotation of said wheel at approximately the end of each of said steps.

20. A toothed wheel, a toothed link oscillatable aboutv two spaced pivots and, normally engaginga tooth on said wheel, cam means-to drive said link about one of said pivots to cause saidlink to drive said wheel, and a second cam means to drive said link about the other of said pivots'for causing said link to disengage said first tooth and engage another tooth on said wheel.

21. In a device for converting strokes of areciprocal universa1 bar, the lengths of which may vary between a limited minimum and a limited maximum, to constant stepped rotary motion; a unit in cooperative relation with said universal bar and carrying at least two driving members; one of which has a constant time-space relation- Ship with the beginning of the forward stroke of said-universal bar, while the other one has a constant time-space relationship with a given fraction of said stroke, the extent of which is shorter than said minimum length; a second unit including at least two links, eachof which is driven by said members in an ordered sequence so that a projected point of one of said links traces a planetary path in which it moves an increment A in one direction, an increment B in a difierent direction, an increment C in yet another direction, then an increment D in a direction somewhat opposite said different direction until it. reaches its initial and normal position, thereby tracing a somewhat quadrilateral figure, the sides of which are formed by said-increments A, B, C and D respectively, the extent of the elongation of the side A and the side C, being constant as the resultant of said predetermined portion of said minimum stroke, while the extent of the elongation of the side B and the side D is variable as the resultant of the remaining portion of the reciprocal stroke from said portion to the end thereof, and a toothed wheel having one tooth normally engaged by said projected point of said one link and adapted to be rotateda predetermined fraction of a revolution by the latter as it moves along a given portion of said path,

irrespective of any variations in the length of said stroke.

22. In-a device for converting variable strokes of a high frequency reciprocal universal bar to rotary motion, a ratchet wheel supported for rotation, a unit in cooperative relation with said universal bar and-carrying at least-two driving members, and a second unit including at least two links each of which is driven by said members in a sequential order so that a projected point of one of said links, which normally engages said ratchet wheel, traces a planetary path in which it moves an increment A in one direction, an increment B in another direction, an increment C in a third direction, and an increment D in a direction different from said second direction, until it reache its initial position in engagement with a different tooth of said ratchet wheel, thereby tracing a somewhat quadrilateral figure, the sides of which are formed by the increments A, B, C and D respectively, said sides A and B being produced during the forward Stroke of said universal bar and consequently as fast as said universal bar makes its forward stroke, while said sides C and D are produced during the backward stroke of said universal bar under the urge of spring means as fast as said universal bar makes its return stroke, said ratchet Wheel being rotated a fraction of a revolution while said projected point is passing along a predetermined increment of said quadrilateral path.

23. In a converting mechanism, a toothed wheel, a toothed link having a single shaft normally in mesh with at least one tooth of said Wheel, a compound support for said link, a reciprocating universal bar, means actuated by the forward stroke of said universal bar including a first cam means to cause said link to first drive said wheel and a second cam means acting against said compound support for said link to disengage said link and move it away from said wheel, and a second means comprising spring power to return said link to its initial position in mesh with another tooth of said wheel.

24. In apparatus of the character described, a ratchet wheel, a double driven free return single pawl to propel said wheel, compound supports for said pawl, driving means carrying compound cams in cooperative relation with said supports, and reciprocally moved means actuating against said driving means to cause sequential movement of said driving means and the sequential action of said cams against said supports.

25. In a device for producing rotary motion in steps, a ratchet wheel, free return pawl means to propel said wheel, an intermediate member forming a support for said pawl means and two driving means to actuate said pawl means, one actuating it directly and the other actuating it through said intermediate member supporting said pawl means.

26. In a motion converting device, a rotary toothed wheel, an oscillatory toothed link in operative mesh with said wheel, a pivoted support for said link, driving means carrying dual cam means to directly drive said link and thereafter to drive it by moving said pivoted support, where by said link is actuated at least twice in succession by said driving means to rotate said wheel a single step, said link being disengaged from one tooth of said wheel and re-engaged with a succeeding tooth the while.

27. In a motion converting device, a ratchet wheel, a pawl to rotate said wheel in steps, said pawl being oscillatable about at least two spaced pivotal centers, a unit member pivotally supported on one of said centers, a support for said pawl pivoted to said unit member on the other of said centers, and means including compound cam means to oscillate said pawl about said centers.

28. In an escapement mechanism, two toothed members normally in mesh, one of said members 22 being movable on a single pivot and having an outer periphery, the other of said members being movable on at least two spaced pivots the axes of which lie outside said periphery and adapted to swing once on each of its pivots while said first member swings once on its pivot, and a driving member carrying elements for effecting the swinging of said other member as aforesaid.

29. In a device for transforming reciprocal strokes of a universal bar into stepped rotary motion, a ratchet wheel, dual controls, a difierential pawl motivated by said dual controls during each of the forward strokes of said universal bar to engage and rotate said ratchet wheel, and driving means cooperating with said controls and rendering said controls effective to cause the disengagement of said pawl from said ratchet wheel when said universal bar, during its forward stroke, travels a predetermined distance, so that further travel of said universal bar beyond said distance will not impart further movement to said ratchet wheel.

30. In an intermittent rotary mechanism, a rotatable driving toothed member, a rotatable driven toothed member, said first member normally having one tooth operatively engaging one tooth of said driven member, a fixed stop and guide member having a straight portion adjacent to and overlapping said driven member and normally contacted by said first tooth, and means to intermittently rotate said driven member by moving said driving member, to disengage the tooth of said driving member from said driven member, to move said driving member into engagement with said stop and guide member, and to re-engage said driving member with another tooth of said driven member, said driving member being free and out of contact with said driven member from the time it is disengaged until the time it is guided to and re-engaged with said driven member.

31. In an intermittent rotary mechanism, a rotatable driving toothed member, a rotatable driven toothed member, said first member normally having one tooth operatively engaging one tooth of said driven member, a fixed stop and guide member having a straight portion adjacent to and overlapping said driven member and normally contacted by said first tooth, and means to intermittently rotate said driven member by moving said driving member, to disengage the tooth of said driving member from said driven member, and to move said driving member into engagement with said stop and guide member, said driving member being free and out of contact with any portion of said mechanism from the time it is disengaged from said driven memher until the time it comes in contact with said guide member, said guide member being adapted to change the direction of movement of said drive member and to guide it into re-engagement with another tooth of said driven member.

SEYED KHALIL.

References Cited in the file of this patent UNITED STATES PATENTS Number Name Date 323,495 Brooks Aug. 4, 1885 514,807 Barron Feb. 13, 1894 624,297 Chapman May 2, 1899 646,287 Hundhausen Mar. 27, 1900 862,076 Hess July 30, 1907 1,012,943 Waldheim Dec. 26, 1911 1,217,290 Farnham et a1 Feb. 27, 1917 1,469,778 Crawley Oct. 9, 1923 2,154,568 Harris Apr. 18, 1939 

